What to know

• Add to Preferred Sources Marta Kostyuk did not have the WTA Finals debut that she would have been hoping for. Kostyuk received a late call-up to play the WTA Finals this year after world number one Elena Rybakina withdrew for medical reasons, enabling the Ukrai...S1
• Every player who has gone 0-3 at the WTA Finals as Marta Kostyuk joins unwanted list which includes Coco GauffS2